Conventionally, there is a technology of etching a SiON film with a resist mask. For example, there is a technology of etching a SiON film with a fluorine-containing gas (including a CHF3 gas). Further, for example, there is a technology of etching a SiON film by using a H2 gas as an etching gas.
Patent Document 1: Japanese Patent Laid-open Publication No. 2003-163349
Patent Document 2: Japanese Patent Laid-open Publication No. H07-106308